Can you reach any servers? Ones you've not played on for example.
Also, we seem to have neglected to ask you to try to log in with all 3rd party scripts removed. Does this change anything. I would also try logging in with Edge - just to see if you can get in.

@freestateza please list specific worlds - different worlds are on differing servers so it will help the developers to track the problem if they know where to look rather than the 100's of worlds that now exist.

Those symptoms sound very like a script error. Try disabling or removing all scripts (or try a browser that doesn't use scripts such as Edge) to see if that solves the problem.

If so, go back and add the scripts one by one, making sure you use the latest versions available. (Many don't work with 17.4 - the latest patch that is out there). The script packs from here are the best available scripts that are tested to work.